Materials handling machine

ABSTRACT

The machine comprises an endless bucket train which is supported by four wheels. The bucket train passes over the first wheel, under the second, over the third, and over the fourth wheel. Between the fourth and first wheels the bucket train hangs freely and is adapted to dig and transport a wide variety of granular materials. The bucket train comprises circular buckets with axial cables extending therebetween. The material is dumped from the bucket train as it travels downwardly between the first and second wheels. The second and fourth wheels are displaced in opposite directions from the first and third wheels so that the material will be dumped at a point which is clear of the upward flight of the buckets. The fourth wheel is mounted on a boom which is swingable about an axis corresponding generally to the axis of the third wheel so that the elevation of the fourth wheel can be changed. The third and fourth wheels are generally in the same plane, while the first wheel is in a different plane, generally parallel to the plane of the third wheel but converging at a small angle toward the fourth wheel. The second wheel is in a plane which is generally perpendicular to the plane of the third wheel. The entire machine is adapted to be suspended from a crane, for use in unloading ships or the like.

United States Patent Wallace, Jr.

14 1 Sept. 5, 1972 [54] MATERIALS HANDLING MACHINE- [72] Inventor: WalterJ. Wallace, Jr.,-Batavia,lll.

[73] Assignee: W. J. Wallace Systems, lnc.,

Batavia, Ill.

[22] Filed: Feb. 26, 1970 21 Appl. No.: 14,356

[52] US. Cl. ..198/93, 198/116, 198/140 [51] Int. Cl ..B65g 15/00 [58] Field of Search ..198/93, 116,168, 140, 151, l98ll52;2l4/14, 15

[56] References Cited UNITED STATES PATENTS 3,435,964 4/1969 Wilkin ..198/168 x 3,378,130 4/1968 Wallace... ..198/116 224,505 2/1880 Alexander ..198/1 16 538,933 5/1895 Ray ..198/116 1 943,121 12/1909 Merian ..198/116 x Primary Examiner-Evon c. Blunk Assistant Examiner-H. S. Lane Att0meyBurmeister, Palmatier & Hamby [57] ABSTRACT The machine comprises an endless bucket train which is supported by four wheels. The bucket train passes over the first wheel, under the second, over the third, and over the fourth wheel. Between the fourth and first wheels the bucket train hangs freely and is adapted to dig and transport a wide variety of granular materials. The bucket train comprises circular buckets with axial'cables extending therebetween. The material is dumped from the bucket train as it travels downwardly between the first and second wheels. The

' second and fourth wheels are displaced in opposite directions from the first and third wheels so that the material will be dumped at a point which is clear of the upward flight of the buckets. The fourthwheel is mounted on a boom which is swingable about an axis corresponding generally to the axis of the third wheel so that the elevation of the fourth wheel can be changed. The third and fourth wheels are generally in the same plane, while the first wheel is in a different plane, generally parallel to the plane of the third wheel but converging at a small angle toward the fourth wheel. The second wheel is in a plane which is generally perpendicular to the plane of the third wheel. The entire machine is adapted to be suspended from a crane, for use in unloading ships or the like.

26Clain$,l0Drawingfigures PATENTEDSEP 82 8.888.888

SHEET 2 [IF 3 MATERIALS HANDLING MACHINE This invention relates to a new and improved materials handling machine of the general type disclosed and claimed in the applicants US Pat. No. 3,378,130, issued April l6, 1968. A machine of this type utilizes an endless train of circular buckets, connected together by cables. The bucket train is supported by a series of wheels so that the major portion of the bucket train hangs freely between two of the wheels which are spaced apart horizontally. The freely hanging portion of the bucket train is adapted to dig and transport a wide variety of granular materials. Thus, a machine of this type is well adapted for unloading bulk granular materials from a ship or other vehicle.

One principal object of the present invention is to provide a new and improved materials handling machine of the foregoing character, which is especially well adapted to be suspended from a crane for use in.

unloading ships or the like. For such service, the machine is lowered through one of the hatches of a ship, so that the lower portion of the bucket train will dig bulk material from the hold of the ship. The material is carried upwardly through the hatch of the ship.

Thus, the present invention provides a materials handling machine in which an endless bucket train is mounted 'on a plurality of supporting wheels, one of which is carried by a swingable boom. The other wheels are mounted on a frame, which can be suspended from a crane, or supported in any other suitable manner. The boom is swingable in a vertical plane, about a horizontal axis on the frame. The bucket train has a freely hanging portion extending between the wheel on the boom and one of the wheels on the frame. The freely hanging portion is adapted-to dig and elevate a wide variety of bulk materials from the hold of a ship or any other place where bulk materials are stored or conveyed. The boom can easily be inserted into the hold of the ship through one of the hatches. By adjusting the boom and turning the machine about its point of suspension, the bucket train can be brought into engagement with all portions of the bulk material in the hold of the ship. I

Preferably, the bucket train is supported on four wheels, including three on the frame and the fourth on the boom. The bucket train hangs freely between the fourth wheel and the first wheel on the frame. After passing over the first wheel, the bucket train passes under the second wheel, over the third wheel, and then along the boom and over the fourth wheel.

The granular material is dumped from the buckets as they travel downwardly'between the first and second wheels. A hopper or the like is preferably provided to catch the dumped material. From the hopper, the material is carried away by a belt conveyor or any other suitable means.

Preferably the first and third wheels are in different planes which are generally parallel but converge at a small angle toward the fourth wheel. The third and fourth wheels are preferably in generally the same plane. It is preferred to mount the second wheel at a lower elevation than the first and third wheels, and in a plane transverse and generally perpendicular to the planes of the first and third wheels.

The first and third wheels are preferably disposed between the second and fourth wheels. In this way, the

granular material is dumped at a point remote from the boom and away from the free hanging portion of the bucket train. The arrangement of the first three wheel is extremely compact so that the. size of the frame is small.

The boom is preferably swingable about a pivot axis which corresponds generally to the axis of the third wheel. The bucket train is normally of the type comprising circular buckets connected together by axially disposed flexible cables. Each bucket is preferably formed with a rounded bottom for smooth engagement with rollers on the supporting wheels.

Further objects, advantages, and features of the present invention will appear from the following description, taken with the accompanying drawings in which:

FIG. 1 is a diagrammatic elevational section showing a materials handling machine to be described as an illustrative embodiment of the present invention, the machine being shown in its position of use, suspended from a crane.

FIG. 2 is a plan view showing the materials handling machine and the supporting crane.

FIG. 3 is an elevational view showing one side of the materials handling machine.

FIG- 4 is an elevational view taken at right angles to FIG. 3.

FIG. 5 is a plan view, taken generally as indicated by the line 5-5 in FIG. 4.

FIG. 6 is a fragmentary elevation, partly in section;

. showing the bucket train employed in the materials handling machine.

FIG. 7 is an end view of one of the buckets, taken along the line 7-7'in'FlG. 6.

FIG. 8 is a fragmentary elevational section showing the bucket train and one of the supporting wheels em ployed in the materials handling machine.

FIG. 9 is a fragmentary section, taken generally along the line 9-9 in FIG. 8.

FIG. 10 is a fragmentary plan view, taken as indicated by the line 10--l0 in FIG. 8.

FIGS. 1 and 2 show the general construction and use of a materials handling machine 20, suspended from a crane 22. The material handling machine 20 utilizes an endless bucket train 24 which is well adapted for unloading a wide variety of granular bulk materials from a ship 26. It will be understood that this use of the materials handling machine is shown by way of example, and that the machine is applicable to the removal of bulk materials from other vehicles or conveyances, and also from storage facilities of many types.

The crane 22 makes it easy to lower a portion of the materials handling machine 20 through a hatch 28 of the ship 26 so that bulk materials can be unloaded from the hold 30 of the ship. The materials handling machine 20 digs the bulk material from the hold and elevates the bulk material through the hatch 28. The bulk material is then delivered to suitable means for carrying away the bulk material. As shown, the bulk material is delivered into a hopper 32 from which the material is discharged upon a belt conveyor 34.

The materials handling machine 20 can be used in connection with any kind of a crane. Thus, it is merely by way of example that the illustrated crane 22 is of a type frequently used for handling containerized shipments. As shown, the crane 22 comprises a tower 36 having wheels 38 adapted to travel along rails or tracks 40. In this way, the entire crane can be moved along the length of the ship 26. The rails 40 extend parallel to the shoreline of the dock 42, alongside which the ship 26 is tied up.

The illustrated crane 22 has a boom 44 which extends horizontally and at right angles to the direction of the rails 40. A carriage 46 is adapted to travel along the boom 44 and is supported by means of rollers 48 running on rails 50. The carriage 46 includes acab 52 for the operator of the crane. A hoist 54 utilizing cables 56 is suspended from the carriage 46. It will be recognized that any desired load can be lifted by the hoist and translated transversely to the ship of the sip 26 by causing the carriage 46 to travel along the rails 50 on the boom 44. As illustrated, the materials handling machine is suspended from the hoist 54. Thus, the machine 20 can readily be moved up or down and also transversely. By causing the crane to travel along the rails 40, the materials handling machine 20 can be moved along the length of the ship 26.

In the illustrated arrangement, the belt conveyor 34 is movably mounted on the tower 36 of the crane 22. The conveyor 34 may be of the type that can be raised and lowered, while also being capable of being extended and retracted. In the illustrated arrangement, the belt conveyor 34 delivers the bulk material to a hopper 60 mounted on the tower 36. By means of one or more chutes 62, the bulk material can be directed from the hopper 60 into a railroad car 64, one or more trucks 66 or any other desired conveyance. Instead of delivering the bulk material into the hopper 60, the conveyor 34' can be arranged to transfer the bulk material to another conveyor 68 which may extend to a point some distance from the crane 22.

A swivel joint 70 is preferably provided between the materials handling machine 20 and the hoist so that the machine can be turned to any desired angle as illustrated in FIGS. 1 and 2. In this way, the machine 20 can be moved into any portion of the hold 30 in the ship 26, so that all portions of the bulk material can be reached by the bucket train 24.

The construction of the materials handling machine 20 is shown in greater detail in FIGS. 3-7. It will be seen from FIGS. 6 and 7 that the bucket train 24 comprises a plurality of buckets 74 which are connected together by flexible elements, preferably the illustrated cables 76. The buckets 74 are preferably circular in cross-section, with annular side walls 78 and rounded bottom walls 80. It is preferred to connect the cables 76 axially to the buckets 74. For this purpose, each of the illustrated buckets 74 has an axial core member 82, welded or otherwise secured to the bottom wall 80 and extending within the bucket along the entire length thereof. The cable 76 are anchored within the opposite ends of the axial member 82 which is preferably tubular in form.

The annular side wall 78 of each bucket 74 preferably tapers toward the bottom wall 80. Each bucket 74 is reinforcedby a plurality of ribs or plates 84 extending radially between the axial member 82 and the annular side wall 78. The buckets 74 can be of either welded or cast construction. Further details of the bucket 74 will be discussed presently in connection with FIGS. 8-10.

The bucket train 24 is supported and driven by a plurality of rotatable wheels. The illustrated construction utilizes four wheels 91, 92, 93 and 94, all of which can' be the same or similar in construction. Between the fourth and first wheels 94 and 91, the bucket train 24 has a free hanging portion 96, adapted to dig and elevate the bulk material. The bucket train 24 is driven in such a direction as to circulate downwardly from the fourth wheel 94 and upwardly to the first wheel 91. After passing over the first wheel 91, the bucket train 24 travels under the second wheel 92 and over the third wheel 93. The bucket train 24 then travels outwardly to the fourth wheel 94 and passes over it.

In accordance with the present invention, the fourth wheel 94 is mounted on the outer end of a swingable boom 98. In this way, the position of the fourth wheel 94 can be adjusted relative to the other three wheels. Preferably, the other three wheels 91-93 are mounted on a frame 100, and the boom 98 is swingable about a horizontal pivot axis on the frame. As shown, the third wheel 93 is rotatable about a shaft 102, and the boom 98 is swingable about the same shaft. Thus, the pivot axis of the boom 98 corresponds to the rotary axis of the third wheel 93.

Means are provided to raise and lower the boom 98 relative to the frame 100. As shown, a cable 104 is connected to the boom 98 and is wound upon a winch or hoist 106, mounted on the frame 100. The winch 106 may incorporate an electrical driving motor. Any other suitable means may be employed to raise and lower the boom 98.

The provision of the boom 98 makes it easy to lower the free hanging portion 96 of the bucket train 24 into the hold of the ship 26 through the hatch 28. If necessary, the boom 98 can be lowered to provide clearance for the passage of the boom, the wheel 94, and the free hanging portion 96 of the bucket train 24 through the hatch 28. The boom 98 can then be raised so that it will extend into the most remote portions of the hold 30. As shown, the hatch opening 28 is much smaller than the hold 30. Thus, the ship 26 has portions 108 around the hatch 28 which overhang the edge portions of the hold 30. The boom 98 is adapted to extend under these overhanging portions 108, as shown to best advantage in FIG. 1.

As shown in FIGS. 3 and 5, the first and third wheels 91 and 93 are mounted in different planes on the frame 100. In this way, portions of the bucket train 24 are caused to travel in different planes. These planes of the first and third wheels 91 and 93 are generally parallel, but actually converge at a small angle toward the fourth wheel 94. The third and fourth wheels 93 and 94 may be in the same plane.

To carry the bucket train 24 between the different planes of the first and third wheels 91 and 93, the second wheel 92 is mounted on the frame in a transverse plane, roughly perpendicular to the planes of the wheels 91 and 93. This arrangement of the wheels 91, 92 and 93 is particularly compact, which is especially advantageous when the mounting frame 100 is to be suspended from a crane.

As previously indicated, the bucket train 24 passes over the first wheel 91 and downwardly to the second wheel 92. The granular material is dumped from the buckets 74 as they pass downwardly between the first and second wheels. As previously indicated, the granular material drops into the hopper 32.

In accordance with another feature of the present invention, the second wheel 92 is positioned remotely relative to the position of the fourth wheel 94. In this way, the first and third wheels 91 and 93 are disposed between the second and fourth wheels 92 and 94. This arrangement is highly advantageous because the buckets are dumped at a point which is completely clear of the free hanging portion 96 of the bucket train. Moreover, the dumping point is away from the boom 98 and clear of the portion of the bucket train 24 extending between the third and fourth wheels 93 and 94.

Means are provided to drive one or more of the wheels 91-94 so as to circulate the bucket train 24. In this case, the second wheel 92 is driven by an electric motor 110 through a gear reduction drive 1 12.

As previously indicated, a swivel joint 70 is preferably provided between the frame 100 and the hoist 54. This joint makes it possible to turn the materials handling machine 20 to any angle that may be desired. Several such positions of the machine are shown in FIG. 2. It is possible to reach the farthest corners of the hold 30 by swiveling the machine 20 and adjusting the angle of the boom 98. While it is possible to turn the machine by hand, it is preferred to provide a motor drive 114 (FIG. 4) to turn the machine at the swivel joint 70.

As previously indicated, the bulk material flows out of the hopper 32 and. onto the belt conveyor 34. In order to maintain the position of the conveyor 34 under the hopper 32, it is preferred to provide a universal joint 116 between the hopper and the supporting frame of the conveyor 34. The joint 116 provides for swiveling and swinging movement between the hopper 32 and the conveyor 34.

Additional details of the bucket train 24 and the supporting wheels are shown in FIGS. 8-10. As previously indicated, each bucket 74 has a tapered annular side wall 78 and a rounded bottom wall 80. It will be seen that the rounded bottom wall 80 merges with the side wall 78 along a smooth curve.

As already indicated, each bucket 74 has an axial tubular member 82 to which the cables 76 are connected. In the illustrated construction, the ends of the cables 76 are anchored within tubular connectors 120, adapted to be screwed into the axial members 82 of the buckets 74. The tubular connectors 120 have enlarged heads 122 which project beyond the axial members 82 at the open ends of the buckets 74. However, at the bottom of each bucket 74 the tubular connector 120 is recessed into the axial supporting member 82 of the bucket. The head 122 is received within an enlarged bore or opening 124 formed in the axial member 82 adjacent the bottom wall 80 of the bucket.

Any bucket 74 can be removed from the bucket train by .unscrewing the connecting members 120 from the axial member 82. Thus, it is easy to reduce or increase the number of buckets in the bucket train.

All of the wheels 91-94 can be of basically the same construction. Such construction is disclosed and claimed in the applicants prior US. Pat. No. 3,378,130, issued April 16, 1968. However, the buckets 74 have been improved over the construction shown in such patent and the interaction between the buckets and wheels has also been improved. It may be considered that FIGS. 8-10 illustrate the third wheel 93, but the construction is typical of all of the wheels 91-94. The illustrated wheel 93 has a central hub or core 130 which is generally cylindrical in shape. To engage and guide the cables 76, the wheel 93 is provided with a plurality of angularly spaced arms 132, projecting outwardly from the hub 130. A peripheral groove 134 is formed in each arm 132 to receive the cables 76. On each side of the groove 134, each arm 132 is provided with inclined ramps or horns 136 to guide the cables into the groove.

Each arm 132 is also provided with a cluster of four rollers 138 to synchronize the movement of the buckets 74 with the rotation of the wheel 93. The rollers 138 also assist in guiding the cables 76 into the groove 134.

The four rollers 138 are at right angles at one another so as to form a square pattern, as will be evident from FIG. 10. With respect to the cables 76, the rollers 138 are angularly disposed, at angles of 45 to the radial plane defined by the axes of the cables and the buckets.

Each of the illustrated rollers 138 has a periphery which is generally V-shaped in cross-section. Thus, each roller 138 has two peripheral surfaces 140 which are frustoconical in shape. As shown, the surfaces 140 are approximately at right angles to each other, and at angles of approximately 45 to the central radial plane of. the roller.

The rollers 138 are adapted to engage the buckets 74 so as to drive the buckets or synchronize the rotation of the wheel with the movement of the buckets. In the case of the second wheel 92, the rollers 138 drive the buckets. The other wheels, 91, 93 and 94, are driven by the buckets which engage the rollers to synchronize the movement of the wheels with that of the buckets.

In each cluster of four rollers 138, two of the rollers are adapted to engage the rounded bottom wall 80 of one of the buckets 74, while the other two rollers are engageable with the end of the connector 120 on the next bucket along the bucket train. The rollers 138 on the second wheel 92 engage the rounded bottom walls 80 of the buckets 74 so as to drive the bucket train 24. It will be realized that the rollers 138 roll smoothly along the rounded walls 80 of the buckets. Thus, the bucket train 74 passes around the wheel very smoothly and with a minimum of noise and vibration. The

smooth action between the rollers and the rounded bottom walls of the buckets makes it possible to drive the buckets at an extremely high speed. In this way, the machine is able to dig and convey the bulk material at an extremely rapid rate.

It will be recognized that it is the frusto-conical surfaces 140 of the rollers 138 which engage the buckets 74. Those rollers which engage the rounded bottom walls of the buckets do not engage the ends of the connectors 120, because they are recessed into or flush with the bottom wall. Thus, the driving action of the rollers 138 is directly upon the rounded bottom walls 80 of the buckets.

As to those wheels which are driven by the buckets 74, the ends of the connectors at the open ends of the buckets engage the rollers 138, but only with enough force to synchronize the wheels with the buckets. The rollers 138 have a smooth rolling action along the ends of the connectors 120 as the bucket train passes around the wheel.

The wheel 93 is provided with a pair of additional rollers 144, adapted to engage the side walls 78 of the buckets 74 so as to hold the buckets outwardly. As will be seen from FIG. 9, the rollers 144 are preferably angled so as to form a seat for the buckets. By virtue of the rollers 144, the buckets are positioned so that the cables 76 extend along the pitch circle defined by the cable grooves 134 in the arms 132. The connectors 120 are formed with flaring portions 146 to support the cables along such pitch circle. The rollers 144 assist in the smooth movement of the buckets 74 into and out of engagement with the wheels 91-94.

As shown in FIGS. 9 and 10, the wheel 93 is provided with end flanges 148 projecting outwardly beyond the central core or hub 130. Such flanges are also preferably provided on the first and fourth wheels 91 and 94. In the case of the second wheel 92, these flanges may be omitted to assist in the unobstructed dumping of the bulk material from the buckets 74 as they travel downwardly between the first and second wheels 91 and 92.

It may be helpful to summarize the operation of the materials handling machine 20. As shown in FIGS. 1 and 2, the machine is suspended from the hoist 54 on the crane 22 so that the lower portion of the machine can be inserted into the hold 30 of the ship 26 through the open hatch 28. The upper portion of the machine 20 projects above the hatch. The boom 98 may be swung downwardly for easy insertion through the hatch 28, and then may be swung upwardly so as to extend under the overhanging portion 108 of the ship 26. The boom 98 is raised and lowered by operating the winch 106.

The machine 20 is steered to the desired angle tuming the the swivel joint 70. The motor drive 114 may be utilized to turn the machine. The bucket train 24 is driven by the motor 110 which causes the second wheel 92 to rotate. The buckets in the lower, free hanging portion 96 of the bucket train 24 dig into the bulk material and carry it upwardly through the hatch 28. The loaded buckets then pass over the first wheel 91 and downwardly to the second wheel 92. The buckets 74 are thus inverted so that the bulkmaterial is dumped out of the buckets and into the hopper 32. The bulk material flows out of the hopper and on to the belt conveyor 34. Any other suitable means may be employed to carry away the bulk material.

The empty buckets pass upwardly between the second and third wheels 92 and 93, and then along the boom 98 to the fourth wheel 94. The buckets then travel downwardly so as to pick up another load of bulk material.

The entire hold 30 of the ship 26 can be emptied by moving the machine 20 to a series of positions. The entire machine 20 can be raised and lowered by operating the hoist 54 on the crane 22. The boom 98 can be raised and lowered by operating the wirich 106. Moreover, the machine can be turned about the swivel joint 70. In this way, the bucket train 24 can be moved into the farthest comers of the hold.

The arrangement of the first three rollers 91-93 is particularly compact so as to facilitate the movement of the machine through the hatch 28. The first and third rollers 91 and 93 are in different planes, converging at a small angle toward the fourth roller 94. Basically, the first and third rollers 91 and 93 are opposite each other and at substantially the same elevation, while the second roller 92 is at a lower elevation and in a plane transverse to the planes of the rollers 91 and 93. The material is dumped as the buckets 74 travel downwardly, toward and under the second wheel 92. This arrangement makes it possible to dump the bulk material at a position which is away from the boom 98 and the upwardly traveling flight of the loaded buckets. The machine 20 can be turned to a variety of positions while still keeping the dumping point clear of the bucket train.

The bucket train 24 passes smoothly and quietly around the wheels 91-94. Such movement is made possible by the smooth rolling engagement between the rollers 138 and the round bottom walls of the buckets 74. It is possible to circulate the bucket train at an extremely high speed while still maintaining smooth and quiet operation. Thus, the materials handling machine 20 has a high capacity, in that it can dig and transport the bulk material at an extremely rapid rate.

lclaim: 1. A materials handling machine, comprising a flexible endless bucket train for digging, elevating and dumping loose materials,

said bucket train including a plurality of spaced buckets with flexible tension elements therebetween,

first, second, third and fourth wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, over said third wheel and over said fourth wheel,

said bucket train hanging freely along a catenary curve in a substantially vertical plane between said fourth and first wheels,

said fourth and first wheels being spaced apart horizontally in planes closely similar to the plane of said catenary curve,

and means for driving at least one of said wheels to circulate said bucket train in a direction to travel upwardly along said catenary curve-to said first wheel, downwardly between said first and second wheels, upwardly between said second and third wheels, over said third and fourth wheels, and downwardly from said fourth wheel along said catenary curve,

said bucket train being effective to dig any loose material disposed along said catenary curve,

said first and third wheels being generally opposite each other and in different planes closely similar to the plane of said fourth wheel,

said second wheel being in a plane extending at a considerable angle to the horizontal and transversely to the planes of said first and third wheels to produce dumping of said buckets between said first and second wheels.

2. A machine according to claim 1,

in which said buckets are circular in cross section and disposed axially along said bucket train,

said tension elements comprising flexible cable elements extending axially between said buckets.

3. A machine according to claim 1,

in which said first and third wheels are generally at the same elevation and are in generally vertical planes converging at the locality of said fourth wheel.

4. A machine according to claim 1,

in which said first and third wheels are in generally vertical planes which are generally parallel but converging at a small angle so as to meet in the locality of said fourth wheel.

5. A machine according to claim 1,

in which said second wheel is in a generally vertical plane generally perpendicular to the planes of said first and third wheels.

6. A machine according to claim 1,

in which said first and third wheels are generally at the same elevation andin generally vertical planes converging at a small angle,

the plane of said third wheel being substantially the same as the plane of said fourth wheel,

the plane of said first wheel being substantially the same as the plane of said catenary curve.

7. A machine according to claim 1,

including a boom for supporting said fourth wheel,

said boom being swingable about a generally horizontal axis to change the elevation of said fourth wheel relative to said first and third wheels.-

8. A machine according to claim 7,

in which said boom is swingable about an axis in the locality of said first and third wheels.

9. A machine according to claim 7,

including mean for raising and lowering said boom by swinging said boom about said axis thereof.

10. A machine'according to claim 1,

including a boom for supporting said fourth wheel, said boom being swingable about a generally horizontal axis in the locality of said first and third wheels,

and means for raising and lowering said boom by swinging itabout said axis thereof to change the elevation of said fourth wheel.

11. A machine according to claim 10,

in which said first and third wheels are in planes converging at a small angle so as to meet in the locality of said fourth wheel,

said second wheel being in a generally vertical plane generally perpendicular to the planes of said first and third wheels.

12. A machine according to claim 10,

in which said second wheel is on the remote side of said first and third wheels from said fourth wheel. 13. A machine according to claim 1,

' in which said second and fourth wheels are displaced a flexible endless bucket train for digging, elevating and dumping loose material,

.an additional wheel rotatably mounted on the outer end portion of said boom,

said bucket train passing over said additional wheel and said first wheel and hanging freely along a catenary curve between said additional wheel and said first wheel,

said first wheel and said additional wheel being disposed in generally vertical planes corresponding closely to the vertical plane of said catenary curve,

and means for driving at least one of said wheels to circulate said bucket train in a direction to travel over said additional wheel, downwardly and'then upwardly along said catenary curve to dig and elevate any loose material along said catenary curve,

said bucket train then travelling over said first wheel to dump the loose material from the buckets,

said bucket train then travelling back to said additional wheel,

said boom being swingablein a generally vertical direction about said pivot means to change the elevation of said additional wheel and thereby change the elevation of the bucket train along said catenary curve.

16. A machine according to claim 15,

including suspension means on the upper portion of said support for suspending said support from a crane or the like.

17. A machine according to claim 15,

including swivel suspension means connected to the upper portion of said support for suspending said support for swiveling movement about a generally vertical axis.

18. A machine according to claim 15,

including a second rotatable wheel adjacent .said first wheel for guiding said bucket train downwardly and then under said second wheel after passing over said first wheel,

said second wheel causing the loose material to be dumped from said buckets.

19. A machine according to claim 15,

including second and third rotatable wheels adjacent said first wheel,

said bucket train being threaded over said first wheel, under said second wheel, over said third wheel, and then back to said additional wheel,

the loose material being dumped from said buckets -as they travel downwardly from said first wheel and under said second wheel.

20. A machine according to claim 19,

inwhich said first and third wheels have rotary axes which'in the localityof the pivot axis of said boom,

said second wheel being disposed in a generally vertical plane transverse to the planes of said first and third wheels.

.21. A material handling machine,

comprising a flexible bucket train for digging and lifting loose materials,

said bucket train including a plurality of buckets having a generally circular cross section,

said bucket train including a plurality of flexible tension elements extending axially between said buckets,

dumping means including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel,

a fourth generally vertical wheel spaced horizontally a considerable distance from said first wheel relative to the spacing between the buckets in the bucket train,

said bucket train extending between said third and fourth wheels, over said fourth wheel, and then hanging freely along a catenary curve between said fourth and first wheels,

means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material engaged by said buckets along said catenary curve, over said first wheel and downwardly to said second wheel to dump the loose material from said buckets, under said second wheel and upwardly to said third wheel, and over said third wheel to said fourth wheel,

said first and third wheels being generally opposite each other in different planes converging at a small angle so as to meet in the locality of said fourth wheel,

said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels,

the plane of said second wheel intersecting the planes of said first and third wheels along the lines traversed by said bucket train in travelling between said first and second wheels and then between said second and third wheels,

said second wheel being positioned on the opposite side of the position of said first and third wheels relative to the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve.

22. A materials handling machine,

comprising a flexible bucket train for digging and lifting loose materials,

said bucket train including a plurality of buckets having a generally circular cross section,

said bucket train including a plurality of flexible tension elements extending axially between said buckets,

dumping means including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel,

a fourth generally vertical wheel spaced horizontally a considerable distance from said first wheel relative to the spacing between the buckets in the bucket train,

said bucket train extending between said third and fourth wheels, over said fourth wheel, and then hanging freely along a catenary curve between said fourth and first wheels,

means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material engaged by said buckets along said catenary curve, over said first wheel and downwardly to said second wheel to dump the loose material from said buckets, under said second wheel and upwardly to said third wheel, and over said third wheel to said fourth wheel,

said first and third wheels being generally opposite each other in different planes converging at a small angle so as to meet in the locality of said fourth wheel,

said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels,

said second wheel being positioned on the opposite side of the position of said first and third wheels relative to the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve.

23. A materials handling machine,

comprising a flexible bucket train for digging and lifting loose materials,

said bucket train including a plurality of buckets having a generally circular cross section,

said bucket train including a plurality of flexible tension elements extending axially between said buckets,

dumping means including first, second and third generally vertical wheels engaging and supporting said bucket train which' passes over said first wheel, under said second wheel, and over said third wheel,

a fourth generally vertical wheel spaced horizontally a considerable distance from said first wheel relative to the spacing betweenthe buckets in the bucket train,

said bucket train extending between said third and fourth wheels, over said fourth wheel, and then hanging freely along a catenary curve between said fourth and first wheels,

means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material engaged by said buckets along said catenary curve, over said first wheel and downwardly to said second wheel to dump the loose material from said buckets, under said second wheel and upwardly to said third wheel, and over said third wheel to said fourth wheel,

said first and third wheels being generally opposite each other in different planes converging at a small angle so as to meet in the locality of said fourth wheel,

said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels.

24. A materials handling machine,

comprising supporting means,

a boom having generally horizontal pivot means connecting the inner end of said boom to said supporting means to provide for swinging movement of said boom in a generally vertical plane,

generally vertical swivel means connected to said supporting means and extending upwardly therefrom to support-said supporting means for swiveling movement about a generally vertical swivel axis,

a flexible endless bucket train for digging, elevating and dumping loose material,

said bucket train including a plurality of spacedbuckets of generally circular cross section and a plurality of flexible tension elements extending axially between said buckets,

dumping means disposed adjacent said pivot means and including first, second and third generally vertical wheels engaging and support said bucket train which passes over said first wheel, under said second wheel, and over said third wheel,

' a fourth wheel rotatably mounted on the outerend portion of said boom,

said fourth wheel being spaced a remote distance from said first wheel relative to the spacing between the buckets in the bucket train,

said bucket train passing between said third and fourth wheels, over said fourth wheel, and hanging freely along a catenary curve between said fourth and first wheels,

said fourth wheel being generally parallel to the vertical plane of swinging movement of said boom,

said first and third wheels being generally opposite each other and in different generally vertical planes converging at a small angle so as to meet in the locality of said fourth wheel,

said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels, I

means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material along said catenary curve,

said bucket train then travelling over said first wheel and downwardly to said second wheel to dump the loose material from the buckets with the aid of the centrifugal force developed as the buckets travel around said second wheel,

said bucket train then travelling under said second wheel, upwardly to said third wheel, over said third wheel, between said third and fourth wheels, and over said fourth wheel to said catenary curve,

and means for swinging said boom about said pivot means for raising and lowering said fourth wheel and thereby raising and lowering said bucket train along said catenary curve,

said second wheel being positioned on the opposite side of the position of said first and third wheels from the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve.

25. A materials handling machine,

comprising supporting means,

a boom having generally horizontal pivot means connecting the inner end of said boom to said supporting means to provide for swinging movement of said boom in agenerally vertical plane,

generally vertical swivel means connected to said supporting means and extending upwardly therefrom to support said supporting means for swiveling movement about a generally vertical swivel axis,

a flexible endless bucket train for digging, elevating and dumping loose material,

said bucket train including a plurality of spaced buckets of generally circular cross section and a plurality of flexible tension elements extending axially between said buckets,

dumping means disposed adjacent said pivot means and including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel,

a fourth wheel rotatably mounted. on the outer end portion of said boom,

said fourth wheel being spaced a remote distance from said first wheel relative to the spacing between the buckets in the bucket train,

said bucket train passing between said third and fourth wheels, over said fourth wheel, and hanging freely along a catenary curve between said fourth and first wheels,

said fourth wheel being generally parallel to the vertical plane of swinging movement of said boom,

said first and third wheels being generally opposite each other and in different generally vertical planes converging at a small angle so as to meet in the locality of said fourth wheel,

said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels,

means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material along said catenary curve,

said bucket train then travelling over said first wheel and downwardly to said second wheel to dump the loose material from the buckets with the aid of the centrifugal force developed as the buckets travel around said second wheel,

said bucket train then travelling under said second wheel, upwardly to said third wheel, over said third wheel, between said third and fourth wheels, and over said fourth wheel to said catenary curve,

and means for swinging said boom about said pivot means for raising and lowering said fourth wheel and thereby raising and lowering said bucket train alongsaid catenary curve.

26. A materials handling machine,

comprising supporting means,

a boom having generally horizontal pivot means connecting the inner end of said boom to said supporting means to provide for swinging movement of said boom in a generally vertical plane,

a flexible endless bucket train for digging, elevating and dumping loose material,

said bucket train including 'a plurality of spaced buckets of generally circular cross section and a plurality of flexible tension elements extending axially between said buckets,

dumping means disposed adjacent said pivot means and including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel,

a fourth wheel rotatably mounted on the outer end portion of said boom,

said fourth wheel being spaced a remote distance from said first wheel relative to the spacing between the buckets in the bucket train,

said bucket train passing between said third and fourth wheels, over said fourth wheel, and hanging freely along a catenary curve between said fourth and first wheels,

said fourth wheel being generally parallel to the vertical plane of swinging movement of said boom,

said first and third wheels being generally opposite each other and in different generally vertical planes converging at a small angle so as to meet in the locality of said fourth wheel,

said second wheel being in a generally vertical plane extending traversely to the planes of said first and third wheels,

' means for driving at least one of said wheels to circuand elevate any loose material along said catenary curve,

said bucket train then travelling over said first wheel and downwardly to said second wheel to dump the loose material from the buckets with the aid of the centrifugal force developed as the buckets travel around said second wheel,

said bucket train then travelling under said second wheel, upwardly to said third wheel, over said third wheel, between said third and fourth wheel, and over said fourth wheel to said catenary curve,

and means for swinging said boom about said pivot means for raising and lowering said fourth wheel and thereby raising and lowering said bucket train along said catenary curve,

, said second wheel being positioned on the opposite side of the position of said first and third wheels from the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve.

222g UNlTED STATES PATENT OTTTCE CERTH ICATE 0F COREC'EWN Patent No. 3,688,893 Dat d September 5, 1972 Inventor(s) Walter J. Wallace, Jr.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 35, After "angle" insert by;

line 36, After "the" (First occurrence) insert -'-machine about-.

Signed and sealed this 30th day of January 1973.

(SEAL) Attest:

EDWARD M.FLETCHEB,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. A materials handling machine, comprising a flexible endless bucket train for digging, elevating and dumping loose materials, said bucket train including a plurality of spaced buckets with flexible tension elements therebetween, first, second, third and fourth wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, over said third wheel and over said fourth wheel, said bucket train hanging freely along a catenary curve in a substantially vertical plane between said fourth and first wheels, said fourth and first wheels being spaced apart horizontally in planes closely similar to the plane of said catenary curve, and means for driving at least one of said wheels to circulate said bucket train in a direction to travel upwardly along said catenary curve to said first wheel, downwardly between said first and second wheels, upwardly between said second and third wheels, over said third and fourth wheels, and downwardly from said fourth wheel along said catenary curve, said bucket train being effective to dig any loose material disposed along said catenary curve, said first and third wheels being generally opposite each other and in different planes closely similar to the plane of said fourth wheel, said second wheel being in a plane extending at a considerable angle to the horizontal and transversely to the planes of said first and third wheels to produce dumping of said buckets between said first and second wheels.
 2. A machine according to claim 1, in which said buckets are circular in cross section and disposed axialLy along said bucket train, said tension elements comprising flexible cable elements extending axially between said buckets.
 3. A machine according to claim 1, in which said first and third wheels are generally at the same elevation and are in generally vertical planes converging at the locality of said fourth wheel.
 4. A machine according to claim 1, in which said first and third wheels are in generally vertical planes which are generally parallel but converging at a small angle so as to meet in the locality of said fourth wheel.
 5. A machine according to claim 1, in which said second wheel is in a generally vertical plane generally perpendicular to the planes of said first and third wheels.
 6. A machine according to claim 1, in which said first and third wheels are generally at the same elevation and in generally vertical planes converging at a small angle, the plane of said third wheel being substantially the same as the plane of said fourth wheel, the plane of said first wheel being substantially the same as the plane of said catenary curve.
 7. A machine according to claim 1, including a boom for supporting said fourth wheel, said boom being swingable about a generally horizontal axis to change the elevation of said fourth wheel relative to said first and third wheels.
 8. A machine according to claim 7, in which said boom is swingable about an axis in the locality of said first and third wheels.
 9. A machine according to claim 7, including mean for raising and lowering said boom by swinging said boom about said axis thereof.
 10. A machine according to claim 1, including a boom for supporting said fourth wheel, said boom being swingable about a generally horizontal axis in the locality of said first and third wheels, and means for raising and lowering said boom by swinging it about said axis thereof to change the elevation of said fourth wheel.
 11. A machine according to claim 10, in which said first and third wheels are in planes converging at a small angle so as to meet in the locality of said fourth wheel, said second wheel being in a generally vertical plane generally perpendicular to the planes of said first and third wheels.
 12. A machine according to claim 10, in which said second wheel is on the remote side of said first and third wheels from said fourth wheel.
 13. A machine according to claim 1, in which said second and fourth wheels are displaced in opposite directions from the position of said first and third wheels.
 14. A machine according to claim 1, including means for collecting and conveying the material dumped from said buckets as said bucket train travels between said first and second wheels.
 15. A materials handling machine, comprising a support, a boom having generally horizontal pivot means connecting the inner end of said boom to said support to provide for swinging movement of said boom in a generally vertical plane, a flexible endless bucket train for digging, elevating and dumping loose material, said bucket train including a plurality of spaced buckets and a plurality of flexible tension elements extending between said buckets, at least a first generally vertical wheel rotatably mounted in the locality of said pivot means, an additional wheel rotatably mounted on the outer end portion of said boom, said bucket train passing over said additional wheel and said first wheel and hanging freely along a catenary curve between said additional wheel and said first wheel, said first wheel and said additional wheel being disposed in generally vertical planes corresponding closely to the vertical plane of said catenary curve, and means for driving at least one of said wheels to circulate said bucket train in a direction to travel over said additional wheel, downwardly and then upwardly along said catenary curve to dig and elevate any loose material along said catenary curve, said bUcket train then travelling over said first wheel to dump the loose material from the buckets, said bucket train then travelling back to said additional wheel, said boom being swingable in a generally vertical direction about said pivot means to change the elevation of said additional wheel and thereby change the elevation of the bucket train along said catenary curve.
 16. A machine according to claim 15, including suspension means on the upper portion of said support for suspending said support from a crane or the like.
 17. A machine according to claim 15, including swivel suspension means connected to the upper portion of said support for suspending said support for swiveling movement about a generally vertical axis.
 18. A machine according to claim 15, including a second rotatable wheel adjacent said first wheel for guiding said bucket train downwardly and then under said second wheel after passing over said first wheel, said second wheel causing the loose material to be dumped from said buckets.
 19. A machine according to claim 15, including second and third rotatable wheels adjacent said first wheel, said bucket train being threaded over said first wheel, under said second wheel, over said third wheel, and then back to said additional wheel, the loose material being dumped from said buckets as they travel downwardly from said first wheel and under said second wheel.
 20. A machine according to claim 19, in which said first and third wheels have rotary axes which in the locality of the pivot axis of said boom, said second wheel being disposed in a generally vertical plane transverse to the planes of said first and third wheels.
 21. A material handling machine, comprising a flexible bucket train for digging and lifting loose materials, said bucket train including a plurality of buckets having a generally circular cross section, said bucket train including a plurality of flexible tension elements extending axially between said buckets, dumping means including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel, a fourth generally vertical wheel spaced horizontally a considerable distance from said first wheel relative to the spacing between the buckets in the bucket train, said bucket train extending between said third and fourth wheels, over said fourth wheel, and then hanging freely along a catenary curve between said fourth and first wheels, means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material engaged by said buckets along said catenary curve, over said first wheel and downwardly to said second wheel to dump the loose material from said buckets, under said second wheel and upwardly to said third wheel, and over said third wheel to said fourth wheel, said first and third wheels being generally opposite each other in different planes converging at a small angle so as to meet in the locality of said fourth wheel, said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels, the plane of said second wheel intersecting the planes of said first and third wheels along the lines traversed by said bucket train in travelling between said first and second wheels and then between said second and third wheels, said second wheel being positioned on the opposite side of the position of said first and third wheels relative to the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve.
 22. A materials handling machine, comprising a flexible bucket train for digging and lifting loose materials, said bucket train including a plurality of buckets having a generally circular cross section, said bucket train including a plurality of flexible tension elements extending axially between said buckets, dumping means including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel, a fourth generally vertical wheel spaced horizontally a considerable distance from said first wheel relative to the spacing between the buckets in the bucket train, said bucket train extending between said third and fourth wheels, over said fourth wheel, and then hanging freely along a catenary curve between said fourth and first wheels, means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material engaged by said buckets along said catenary curve, over said first wheel and downwardly to said second wheel to dump the loose material from said buckets, under said second wheel and upwardly to said third wheel, and over said third wheel to said fourth wheel, said first and third wheels being generally opposite each other in different planes converging at a small angle so as to meet in the locality of said fourth wheel, said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels, said second wheel being positioned on the opposite side of the position of said first and third wheels relative to the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve.
 23. A materials handling machine, comprising a flexible bucket train for digging and lifting loose materials, said bucket train including a plurality of buckets having a generally circular cross section, said bucket train including a plurality of flexible tension elements extending axially between said buckets, dumping means including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel, a fourth generally vertical wheel spaced horizontally a considerable distance from said first wheel relative to the spacing between the buckets in the bucket train, said bucket train extending between said third and fourth wheels, over said fourth wheel, and then hanging freely along a catenary curve between said fourth and first wheels, means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material engaged by said buckets along said catenary curve, over said first wheel and downwardly to said second wheel to dump the loose material from said buckets, under said second wheel and upwardly to said third wheel, and over said third wheel to said fourth wheel, said first and third wheels being generally opposite each other in different planes converging at a small angle so as to meet in the locality of said fourth wheel, said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels.
 24. A materials handling machine, comprising supporting means, a boom having generally horizontal pivot means connecting the inner end of said boom to said supporting means to provide for swinging movement of said boom in a generally vertical plane, generally vertical swivel means connected to said supporting means and extending upwardly therefrom to support said supporting means for swiveling movement about a generally vertical swivel axis, a flexible endless bucket train for digging, elevating and dumping loose material, said bucket train including a plurality of spaced buckets of generally circular cross secTion and a plurality of flexible tension elements extending axially between said buckets, dumping means disposed adjacent said pivot means and including first, second and third generally vertical wheels engaging and support said bucket train which passes over said first wheel, under said second wheel, and over said third wheel, a fourth wheel rotatably mounted on the outer end portion of said boom, said fourth wheel being spaced a remote distance from said first wheel relative to the spacing between the buckets in the bucket train, said bucket train passing between said third and fourth wheels, over said fourth wheel, and hanging freely along a catenary curve between said fourth and first wheels, said fourth wheel being generally parallel to the vertical plane of swinging movement of said boom, said first and third wheels being generally opposite each other and in different generally vertical planes converging at a small angle so as to meet in the locality of said fourth wheel, said second wheel being in a generally vertical plane extending transversely to the planes of said first and third wheels, means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material along said catenary curve, said bucket train then travelling over said first wheel and downwardly to said second wheel to dump the loose material from the buckets with the aid of the centrifugal force developed as the buckets travel around said second wheel, said bucket train then travelling under said second wheel, upwardly to said third wheel, over said third wheel, between said third and fourth wheels, and over said fourth wheel to said catenary curve, and means for swinging said boom about said pivot means for raising and lowering said fourth wheel and thereby raising and lowering said bucket train along said catenary curve, said second wheel being positioned on the opposite side of the position of said first and third wheels from the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve.
 25. A materials handling machine, comprising supporting means, a boom having generally horizontal pivot means connecting the inner end of said boom to said supporting means to provide for swinging movement of said boom in a generally vertical plane, generally vertical swivel means connected to said supporting means and extending upwardly therefrom to support said supporting means for swiveling movement about a generally vertical swivel axis, a flexible endless bucket train for digging, elevating and dumping loose material, said bucket train including a plurality of spaced buckets of generally circular cross section and a plurality of flexible tension elements extending axially between said buckets, dumping means disposed adjacent said pivot means and including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel, a fourth wheel rotatably mounted on the outer end portion of said boom, said fourth wheel being spaced a remote distance from said first wheel relative to the spacing between the buckets in the bucket train, said bucket train passing between said third and fourth wheels, over said fourth wheel, and hanging freely along a catenary curve between said fourth and first wheels, said fourth wheel being generally parallel to the vertical plane of swinging movement of said boom, said first and third wheels being generally opposite each other and in different generally vertical planes converging at a small angle so as to meet in the locality of said fourth wheel, said second wheel being in a generally vertical plane extending transversely to the planes of said first and thiRd wheels, means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material along said catenary curve, said bucket train then travelling over said first wheel and downwardly to said second wheel to dump the loose material from the buckets with the aid of the centrifugal force developed as the buckets travel around said second wheel, said bucket train then travelling under said second wheel, upwardly to said third wheel, over said third wheel, between said third and fourth wheels, and over said fourth wheel to said catenary curve, and means for swinging said boom about said pivot means for raising and lowering said fourth wheel and thereby raising and lowering said bucket train along said catenary curve.
 26. A materials handling machine, comprising supporting means, a boom having generally horizontal pivot means connecting the inner end of said boom to said supporting means to provide for swinging movement of said boom in a generally vertical plane, a flexible endless bucket train for digging, elevating and dumping loose material, said bucket train including a plurality of spaced buckets of generally circular cross section and a plurality of flexible tension elements extending axially between said buckets, dumping means disposed adjacent said pivot means and including first, second and third generally vertical wheels engaging and supporting said bucket train which passes over said first wheel, under said second wheel, and over said third wheel, a fourth wheel rotatably mounted on the outer end portion of said boom, said fourth wheel being spaced a remote distance from said first wheel relative to the spacing between the buckets in the bucket train, said bucket train passing between said third and fourth wheels, over said fourth wheel, and hanging freely along a catenary curve between said fourth and first wheels, said fourth wheel being generally parallel to the vertical plane of swinging movement of said boom, said first and third wheels being generally opposite each other and in different generally vertical planes converging at a small angle so as to meet in the locality of said fourth wheel, said second wheel being in a generally vertical plane extending traversely to the planes of said first and third wheels, means for driving at least one of said wheels to circulate said bucket train in a direction to travel downwardly and then upwardly along said catenary curve between said fourth and first wheels to dig and elevate any loose material along said catenary curve, said bucket train then travelling over said first wheel and downwardly to said second wheel to dump the loose material from the buckets with the aid of the centrifugal force developed as the buckets travel around said second wheel, said bucket train then travelling under said second wheel, upwardly to said third wheel, over said third wheel, between said third and fourth wheel, and over said fourth wheel to said catenary curve, and means for swinging said boom about said pivot means for raising and lowering said fourth wheel and thereby raising and lowering said bucket train along said catenary curve, said second wheel being positioned on the opposite side of the position of said first and third wheels from the position of said fourth wheel whereby the buckets are dumped remotely from said catenary curve. 